Heretofore, for the production of L-alanine, a process in which L-aspartic acid is subjected to enzymatic decarboxylation (Japanese Published Examined Patent Application No. 7560/1971), a process in which fumaric acid is led to L-aspartic acid which is then subjected to enzymatic decarboxylation (Japanese Published Unexamined Patent Application No. 268691/1990), etc. have been employed. There are also known a process for producing L-alanine from lactic acid and an ammonia donor by using D-alanine-requiring E. coli (Japanese Published Unexamined Patent Application No. 36196/1987), a fermentation process with Corynebacterium tumescens using a carbohydrate (Japanese Published Examined Patent Application No. 14298/1961), etc.
The known processes for producing L-alanine by fermentation are disadvantageous in that the amounts of the product accumulated in the culture broth are small, the yields are low, the production rates are low, the culturing requires a long time, and so on. Therefore, these processes are little practical in the industrial production of L-alanine. Also a report has been made on fermentation production of D,L-alanine in high yields (Japanese Published Examined Patent Application No. 797/1982). However, this process is not industrially advantageous because the produced alanine is a racemic mixture of D- and L-forms, thereby necessitating a step of optical resolution of the D- and L-forms in order to obtain L-alanine.